In the computer industry, a database typically refers to a collection of information stored in a specific structure. Furthermore, the specific structure normally arranges data as a plurality of objects commonly consisting of queries and tables. A database management system (DBMS) functions as a control system for the database. Different types of DBMSs exist for different types of data models; moreover, data models are both a way of structuring data and a way of defining operation performable on data.
One common DBMS is a relational database management system (RDBMS) which is so named because it uses a relational data model, generally formed from theory and predicate logic. A RDBMS has numerous tables where the system maintains data collection in rows and columns. A common RDBMS used in conjunction with databases is a sever using Transact-Structured Query Language. Structured Query Language (SQL) is a programming language commonly used in databases with several variations available, typically in proprietary form.
In a typical database network, a relational database management system (RDBMS) operates with database consistency checks (DBCCs) during off-peak hours. In most databases, there exists a source and a snapshot database when a DBCC takes place. The source database contains the database as a whole, whereas the database snapshot contains a sparse copy of the database. Before a user performs a database transaction, a system makes copies of each page the user is changing in the source database. This allows the DBCC to function in regards to a consistent point of time. A reason for creating snapshots is to allow for corrections of bad transactions.
The DBCC reads the pages from the database snapshot if the snapshot is present. If the page being read by the DBCC has been changed since the snapshot was created, then the version of the page in the DB snapshot is used; if not, then the source database page is used. In this operation, the DBCC does not utilize pages changed by an ongoing operation, and typically performs a fact-matching algorithm. The system reads an internal data structure in disk-allocation-order. As the system performs the reads, it generates and stores pieces of information called facts in an internal storage structure. After completion of reads, the system matches and aggregates the stored facts to determine if any incorrect facts are present. Consequently, a large number of checks are performed for just a single pass over the database structure. The snapshot database and the fact-matching algorithm consume a large amount of disk space, which is proportional to a rate of change in a source database since pages are copied when they are modified by a user transaction.